We propose to develop a set of molecular tools to link gene expression to, and to study the role of specific neural circuits in, visual perception and behavior. These tools will be adapted for work in non-human primates, which have distinct advantages in our knowledge of the functional anatomy of neural circuits, the functional architecture of cortex, the ability to study complex behaviors and to combine physiological and behavioral studies in awake, behaving animals, and because of their close relationship with humans. The components of the project include developing gene microarrays based on an expression library derived from the monkey cerebral cortex, high throughput techniques for studying patterns of gene expression involved in specific behaviors, anatomical studies of the patterning of gene expression relative to cortical functional architecture and cell type, developing viral vectors for delivering genes to neurons, reversible inactivation of specific cell classes using molecular tools, and a cortical plasticity model for monitoring changes in gene expression and altering function by changing levels of gene expression via viral transfection. Once developed, these techniques will make possible a top-down understanding of the link between patterns of gene expression and behavior. They will also make it possible to alter gene expression in higher animals for the study of neural mechanisms of behavior.